阅读说明：本技术 具有改进的壳体耐用性的卷尺 (Tape measure with improved housing durability ) 是由 亚当·巴克斯特 乔纳森·希伯特·贝克威思 塞西尔·维尔松 弗拉德·帕德兰吉纳 于 2019-07-12 设计创作，主要内容包括：该卷尺装置可以包括具有孔口的壳体、包围在壳体内的卷轴组件,以及尺身,该尺身具有配置为从壳体延伸穿过孔口的第一端和配置为缠绕在卷轴组件上的第二端。壳体可以包括第一半壳和第二半壳。卷轴组件可以被配置成交替地允许尺身通过孔口从卷轴组件抽出或者在孔口中被接收而到达卷轴组件上。第一半壳和第二半壳可以经由螺纹紧固件接合在一起,该螺纹紧固件插入到形成在第一半壳和第二半壳的对应部分中的螺钉凸台的相应部分中。配合特征可设置在第一半壳和第二半壳上,以便于接合第一半壳和第二半壳。至少一些配合特征可以比其它配合特征长,或者螺钉凸台的直径约为螺纹紧固件的直径的1.5倍至2.5倍。(The tape measure device may include a housing having an aperture, a reel assembly enclosed within the housing, and a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly. The housing may include a first half shell and a second half shell. The reel assembly may be configured to alternately allow the blade to be drawn from the reel assembly through the aperture or received in the aperture onto the reel assembly. The first and second half shells may be joined together via threaded fasteners inserted into respective portions of screw bosses formed in corresponding portions of the first and second half shells. Mating features may be provided on the first and second half shells to facilitate joining the first and second half shells. At least some of the mating features may be longer than others, or the diameter of the screw boss may be about 1.5 to 2.5 times the diameter of the threaded fastener.)

1. A tape measure device comprising:

a housing having an aperture, the housing comprising a first half shell and a second half shell;

a spool assembly enclosed within the housing; and

a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly;

wherein the reel assembly is configured to alternately allow the blade to be drawn from or received in the aperture onto the reel assembly,

wherein the first and second half shells are joined together via threaded fasteners inserted into respective portions of screw bosses formed in corresponding portions of the first and second half shells,

wherein mating features are provided on the first and second half shells to facilitate joining the first and second half shells, an

Wherein at least some of the mating features are longer than others of the mating features, or the screw boss has a diameter that is about 1.5 to 2.5 times a diameter of the threaded fastener.

2. The apparatus of claim 1, wherein the at least some mating features are longer than the other mating features, and the screw boss has a diameter that is about 1.5 to 2.5 times a diameter of the threaded fastener.

3. The apparatus of claim 1, wherein the at least some mating features are about 45% to about 55% longer than the other mating features.

4. The device of claim 3, wherein the at least some mating features include protruding members disposed at the first half-shell to extend into corresponding receiving slots disposed at the second half-shell.

5. The device of claim 4, wherein the protruding member is a housing alignment protruding member disposed at a bottom portion of the housing along which the blade extends before extending through the aperture.

6. The device of claim 1, wherein the at least some mating features are about 8.3% to about 9.3% of a total width of the first and second half-shells.

7. The device of claim 6, wherein the at least some mating features include protruding members disposed at the first half-shell to extend into corresponding receiving slots disposed at the second half-shell.

8. The apparatus of claim 7, wherein the protruding member is a housing alignment protruding member disposed at a keyed area defined at a bottom portion of the housing along which the blade extends before extending through the aperture.

9. The device of claim 1, wherein the mating feature comprises a protruding member disposed only on the first half-shell to extend into a corresponding receiving slot disposed only on the second half-shell.

10. The device of claim 1, wherein the screw boss has a diameter that is about 7.8% to about 8.8% of the defined diameter of the first and second half shells.

11. The device of claim 1, wherein the screw boss occupies about 2% to about 3% of a cross-sectional area enclosed by the first and second half shells.

12. The device of claim 1, wherein the screw boss has a diameter of about 7.8% to about 8.8% of the defined diameter of the first and second half shells, and

wherein the screw boss occupies about 2% to about 3% of a cross-sectional area enclosed by the first and second half shells.

13. A tape measure device comprising:

a housing having an aperture, the housing comprising a first half shell and a second half shell;

a spool assembly enclosed within the housing; and

a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly;

wherein the reel assembly is configured to alternately allow the blade to be drawn from or received in the aperture onto the reel assembly,

wherein the first and second half shells are joined together via mating features provided on the first and second half shells so as to join the first and second half shells, an

Wherein at least some of the mating features are about 45% to about 55% longer than other mating features.

14. The device of claim 13, wherein the at least some mating features include protruding members disposed at the first half-shell to extend into corresponding receiving slots disposed at the second half-shell.

15. The apparatus of claim 14, wherein the protruding member is a housing alignment protruding member disposed at a keyed area defined at a bottom portion of the housing along which the blade extends before extending through the aperture.

16. The apparatus of claim 13, wherein the at least some mating features are about 8.3% to about 9.3% of a total width of the first and second half-shells.

17. The device of claim 13, wherein the mating feature comprises a protruding member disposed only on the first half-shell to extend into a corresponding receiving slot disposed only on the second half-shell.

18. A tape measure device comprising:

a housing having an aperture, the housing comprising a first half shell and a second half shell;

a spool assembly enclosed within the housing; and

a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly;

wherein the reel assembly is configured to alternately allow the blade to be drawn from or received in the aperture onto the reel assembly,

wherein the first and second half shells are joined together via threaded fasteners inserted into respective portions of screw bosses formed in corresponding portions of the first and second half shells,

wherein the diameter of the screw boss is about 1.5 to 2.5 times the diameter of the threaded fastener,

wherein the screw boss has a diameter that is about 7.8% to about 8.8% of the defined diameter of the first and second half shells, and

wherein the screw boss occupies about 2% to about 3% of a cross-sectional area enclosed by the first and second half shells.

Technical Field

Exemplary embodiments relate generally to tape measure devices and, more particularly, to a tape measure having improved durability.

Background

Tape measures have been around for a long time and are a common measuring tool used in many cases to obtain linear measurements. The tape measure may take many forms and may be made of cloth, fiberglass, metal, plastic, etc. The materials used are generally determined by the particular measurement application. For example, tailors and clotheshorses often use flexible tape measures that can be easily manipulated between two hands to measure the distance between the two hands. However, for construction or woodworking applications, it is preferred to use a rigid and typically metal tape measure to allow the tape measure to extend between a first position, where one end of the tape measure is anchored, and a user's position, where the tape measure is paid out from the reel assembly. The reel assembly may have a manual retraction mechanism or a self-retraction mechanism, typically depending on the length of the tape measure. For relatively short tape measures (e.g., 12 or 25 feet), self-retracting mechanisms are very common. For very long tape measures (e.g., greater than 100 feet), a manual retraction mechanism is typically employed.

The reel assembly may also typically be locked in a given position, for example to lock the tape measure with a given amount of metal tape measure blade extending from the housing of the tape measure. The locking mechanism that supports this function is typically embodied as a sliding lock button disposed on the top and/or front of the tape measure housing. The housing is typically formed of half shells that are joined together to enclose the blade and at least one drum and spring that are components of the reel assembly. A common failure mode of tape measures is that the spool and spring or other components of the reel assembly become inoperable following an impact event (e.g., the tape measure is dropped from a height). In some cases, the two half-shells may temporarily separate due to the impact, and the blade itself may become trapped in the gap formed between the two half-shells. In other cases, the drum and spring may disengage due to impact, preventing functional retraction of the blade after it is extended from the housing.

Typical efforts to improve durability have focused on increasing substrate and overmold wall thickness. However, as can be appreciated from the failure modes described above, these efforts are not specific to some of the major failure modes experienced, and may not address these failure modes. In this regard, thickening of portions of the housing does not address the fact that some major failure modes occur due to temporary separation of components of the housing, rather than due to failure of the housing walls themselves. Accordingly, it may be desirable to design a tape measure device with more robust properties to avoid separation of the half shells.

Disclosure of Invention

Some example embodiments may enable a tape measure to be provided having half shells designed to be joined together in a more robust manner. In this regard, for example, some embodiments may provide improved fastening structures and/or mating features between the half-shells to reduce vulnerability to impact damage.

In an exemplary embodiment, a tape measure device is provided. The tape measure device may include a housing having an aperture, a reel assembly enclosed within the housing, and a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly. The housing may include a first half shell and a second half shell. The reel assembly may be configured to alternately allow the blade to be drawn from the reel assembly through the aperture or received in the aperture onto the reel assembly. The first and second half shells may be joined together via threaded fasteners inserted into respective portions of screw bosses formed in corresponding portions of the first and second half shells. Mating features may be provided on the first and second half shells to facilitate joining the first and second half shells. At least some of the mating features may be longer than others, or the diameter of the screw boss may be about 1.5 to 2.5 times the diameter of the threaded fastener.

In another exemplary embodiment, a tape measure device is provided. The tape measure device may include a housing having an aperture, a reel assembly enclosed within the housing, and a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly. The housing may include a first half shell and a second half shell. The reel assembly may be configured to alternately allow the blade to be drawn from the reel assembly through the aperture or received in the aperture onto the reel assembly. The first and second half shells may be joined together via mating features provided on the first and second half shells to facilitate joining the first and second half shells. At least some of the mating features are about 45% to about 55% longer than others of the mating features.

In yet another exemplary embodiment, a tape measure device is provided. The tape measure device may include a housing having an aperture, a reel assembly enclosed within the housing, and a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly. The housing may include a first half shell and a second half shell. The reel assembly may be configured to alternately allow the blade to be drawn from the reel assembly through the aperture or received in the aperture onto the reel assembly. The first and second half shells may be joined together via threaded fasteners inserted into respective portions of screw bosses formed in corresponding portions of the first and second half shells. The diameter of the screw boss may be about 1.5 times to about 2.5 times the diameter of the threaded fastener. The screw boss may have a diameter of about 7.8% to about 8.8% of a defined diameter of the first and second half shells, and the screw boss may occupy about 2% to about 3% of a cross-sectional area enclosed by the first and second half shells.

Drawings

Having thus described some exemplary embodiments in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:

FIG. 1 shows a perspective view of a tape measure device according to an exemplary embodiment;

FIG. 2 shows a block diagram of a tape measure device according to an exemplary embodiment;

FIG. 3 shows a front view of a tape measure device according to an exemplary embodiment to show a half-shell thereof;

fig. 4 shows a perspective view of an interior portion of a first half shell according to an exemplary embodiment;

fig. 5 shows a side view of an interior portion of a first half shell according to an exemplary embodiment;

fig. 6 shows a perspective view of an interior portion of a second half shell according to an exemplary embodiment;

fig. 7 shows a side view of an interior portion of a second half shell according to an exemplary embodiment;

fig. 8 shows a front view of the first and second half shells separated from each other to illustrate the length of the mating features, in accordance with an exemplary embodiment; and

fig. 9 illustrates a perspective view of a self-tapping threaded fastener according to an exemplary embodiment.

Detailed Description

Some exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all exemplary embodiments are shown. Indeed, the examples described and depicted herein should not be construed as limiting the scope, applicability, or configuration of the present disclosure. Rather, these exemplary embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like reference numerals refer to like elements throughout. Further, as used herein, the term "or" should be interpreted as a logical operator that results in true whenever one or more of its operands are true. As used herein, operably coupled should be understood to refer to a direct or indirect connection that, in either case, enables functional interconnection of components operably coupled to one another.

As mentioned above, some exemplary embodiments may be directed to providing a tape measure device that may have an improved impact resistant design. This may be accomplished by providing mating features and/or fastening structures that resist separation of the half-shells in response to an impact, and in some cases may also guide the half-shells back together to ensure that proper alignment of the half-shells is maintained or restored in response to such an impact. According to an exemplary embodiment, fig. 1 shows a perspective view of a tape measure device, fig. 2 shows a block diagram of the device, and fig. 3 shows a front view of the tape measure device to show half-shells thereof.

Referring now to fig. 1-3, an exemplary embodiment of a tape measure device 100 may include a housing 110 including a first housing half 112 and a second housing half 114. First and second housing halves 112 and 114 may house reel assembly 120 and self-retracting assembly 130 therein. The blade 140 (or blade) portion of the device 100 may be wound around the reel assembly 120. The blade 140 may be paid out through an aperture 150 formed in the housing 110. A locking assembly 160 may be provided to lock the reel assembly 120 to prevent the self-retracting assembly 130 from retracting the blade 140 when the locking assembly 160 is engaged.

The blade 140 has an end hook 170 disposed at one end thereof and is secured to the reel assembly 120 at the other end of the blade 140. The end hook 170 may be (temporarily) fixed to an anchor point on the medium to be measured. Once the end hook 170 is secured to the anchor point, the blade 140 can be paid out of the aperture 150 and released from the reel assembly 120. When the desired length of the blade 140 has been paid out, the user can make any necessary markings, readings, etc. associated with the measurement scale markings that may be printed on the blade 140. The measurement scale markings typically measure the length from the end hook 170 in one or more units, with the unit divisions and sub-divisions being clearly marked on the blade 140.

By securing the end hook 170 to the anchor point, the self-retracting assembly 130 (which may be spring-loaded in some cases) may be prevented from retracting the paid-out portion of the blade 140 into the housing 110 (via the aperture 150). Similarly, when the locking assembly 160 is engaged, a force (e.g., a clamping force) may be exerted on the blade 140 to prevent retraction or movement of the reel assembly 120, which may otherwise be inhibited from retracting the paid-out portion of the blade 140 from the retraction assembly 130. However, when the end hook 170 is not anchored and the locking assembly 160 is not engaged, the self-retracting assembly 130 can cause the reel assembly 120 to wind the blade 140 back onto the reel assembly 120.

As described above, the impact may cause the first and second half shells 112, 114 to separate. Although the separation may be temporary and/or small, such separation may still have lasting consequences for the operation of the tape measure device 100. For example, if any portion of the blade 140 is trapped between the first and second housing halves 112 and 114, or if the spring and reel of the self-retracting assembly 130 become misaligned, it may not be possible to continue rewinding the blade 140 onto the reel assembly 120 once the blade 140 is withdrawn from the housing 110. The exemplary embodiment adds the size of certain mating features to the overall size of the tape measure device 100 to achieve an optimal balance between the size and weight of the tape measure device 100 and its robustness.

In this regard, the size of the reel assembly 120 (e.g., the diameter of the reel) may be an important determinant of the minimum size of the tape measure device 100. The housing 110, which desirably remains a light and compact structure, must have at least sufficient height (H), length (L), and width (W) to fit into the reel assembly 120 when the entire length of the blade 140 is stored on the reel assembly 120. The diameter of the reel assembly 120 may therefore be referred to as the "defined diameter" of the tape measure device 100. The height (H) and length (L) dimensions of the diameter control housing 110 (and thus also the first and second half shells 112 and 114) are defined. The width of the reel assembly 120 also determines the minimum width of the tape measure device 100, and the width (W) of the housing 110 will ideally remain relatively close to the minimum width.

Some exemplary embodiments may define optimal characteristics for certain fastening structures or mating features for joining first and second half shells 112 and 114 together. In this regard, for example, the optimal characteristics may be defined in terms of a defined diameter and/or width (W) of the housing 110. The diameter of the fastening structure, such as a screw boss, may be increased relative to a typical screw boss. For example, according to the defined diameter, the diameter of the screw boss may be increased to define an optimal screw boss diameter. Doing so may make the screw bosses less likely to fail due to cracking, flaking, or other failure modes, and may also increase the ability of the screw bosses and fasteners disposed therein to maintain the first and second half shells 112, 114 in contact in response to impact. Meanwhile, depending on the width (W) of the housing 110, the length of the mating feature may be increased to define an optimal mating feature length. Doing so may increase the ability of the tape measure device 100 to avoid shock failure because the longer mating features may ensure that contact and alignment between the first and second half-shells 112 and 114 is maintained during any minor separation of the half-shells, and that alignment will ensure that the first and second half-shells 112 and 114 guide themselves back together in response to a shock.

Fig. 4-8 show various views of first and second half shells 112 and 114 in isolation to facilitate discussion of the optimization of the structure of housing 110 according to an exemplary embodiment. In this regard, fig. 4 shows a perspective view of an interior portion of first housing half 112, and fig. 5 shows a side view of the interior portion of first housing half 112. Fig. 6 shows a perspective view of an interior portion of the second housing half 114, and fig. 7 shows a side view of the interior portion of the second housing half 114. Fig. 8 shows a front view of first and second half shells 112 and 114 separated from one another to illustrate the length of the mating features.

Referring now to fig. 4-8, first and second half shells 112 and 114 may each include a side wall and an end wall that form a cup-shaped structure. When the first and second half shells 112 and 114 are joined together to form the housing 110, the end wall 200 of the first half shell 112 and the end wall 202 of the second half shell 114 may each extend substantially parallel to one another. Side wall 210 of first housing half 112 may extend substantially perpendicularly away from end wall 200 of first housing half 112. However, there may be a curved transition from end wall 200 of first housing half 112 to side wall 210 of first housing half 112. Similarly, the side wall 212 of the second half-shell 114 may extend substantially perpendicularly away from the end wall 202 of the second half-shell 114. However, there may also be a curved transition from the end wall 202 of the second half-shell 114 to the side wall 212 of the second half-shell 114. A receiving opening 220 may be defined between the sidewalls 210 and 212, and the spool assembly 120 may be received within the receiving opening. As shown in fig. 5 and 7, the defined diameter (D) may be at least partially defined by the radial length (i.e., diameter) of the receiving opening 220.

First and second half shells 112 and 114 converge toward one another at first mating surface 230 and second mating surface 232, respectively. The first and second mating surfaces 230 and 232 each lie in a plane and converge at a common plane when joined together. First mating surface 230 may be disposed at a distal end of sidewall 210 of first housing half 112 and may define a continuous flat surface that is perpendicular to the axis of rotation of reel assembly 120 at or near the outer periphery of the side of first housing half 112 facing second housing half 114. The second mating surface 232 may be disposed at a distal end of the sidewall 212 of the second half-shell 114 and may define a continuous flat surface that is perpendicular to the axis of rotation of the reel assembly 120 at or near the outer periphery of the side of the second half-shell 114 facing the first half-shell 112. When housing 100 is assembled, first and second mating surfaces 230 and 232 may converge toward each other in a common plane to define a nearly continuous enclosure around spool assembly 120 and self-retracting assembly 130 within receiving opening 220.

Screw bosses 240 may be incorporated into the first and second mating surfaces 230 and 232 to enable fasteners (e.g., screws) to be threaded therein to hold the first and second half shells 112 and 114 together. In this regard, the first and second mating surfaces 230 and 232 may be substantially mirror images of each other, and the screw bosses 240 may be positioned to also be mirror images of each other, such that any portion of one of the screw bosses 240 located in the first half shell 112 will align with a corresponding portion of one of the screw bosses 240 located in the second half shell 114 when the first and second mating surfaces 230 and 232 are mated together.

Screw boss 240 may be a mounting feature formed as a substantially hollow cylindrical structure configured to receive a screw in its interior hollow portion. Although the screw bosses 240 need not be completely cylindrical in shape, a generally cylindrical structure is formed (e.g., during molding) from the base material used to form the first and second housing halves 112 and 114 (e.g., resin, plastic, polymer, or other rigid material, such as Acrylonitrile Butadiene Styrene (ABS)). The screw boss 240 may be threaded. However, in an exemplary embodiment, the screw boss 240 may be initially formed without any threads therein, and the thread forming fastener 300 (see fig. 9) may be used to form threads in the screw boss 240 when the thread forming fastener 300 is inserted therein.

The screw bosses 240 may be formed to have substantially the same Diameter (DB) for each screw boss 240 and portions thereof. Further, the Diameter (DB) of the screw boss 240 may be optimized according to the defined diameter (D), according to the cross-sectional area enclosed by the convergence of the first and second mating surfaces 230, 232 and/or according to the Diameter (DF) of the thread forming fastener 300 (see fig. 9). In this regard, for example, the Diameter (DB) of the screw boss 240 may be about twice the Diameter (DF) of the thread forming fastener 300 (e.g., from 1.5x to 2.5 x). In this example, if the Diameter (DF) of the thread forming fastener 300 is 0.125 inches, the Diameter (DB) of the screw boss 240 may be about 0.25 inches.

Additionally or alternatively, the Diameter (DB) of the screw boss 240 may be configured to occupy approximately 2.4% (e.g., from 2% to 3%) of the cross-sectional area encompassed by the convergence of the first and second mating surfaces 230, 232. Thus, for this example in which the Diameter (DB) of the screw boss 240 is about 0.25 inches, the cross-sectional area enclosed by the convergence of the first and second mating surfaces 230 and 232 (e.g., the area enclosed, perpendicular to the centerline of the housing, by a line drawn around the perimeter of the housing at the convergence of the first and second half shells 112 and 114, the substrate included, and the overmold) may be about 8.14 square inches.

Additionally or alternatively, the Diameter (DB) of the screw boss 240 may be configured to be about 8.3% (e.g., from about 7.8% to about 8.8%) of the ratio to the defined diameter (D). It is generally advantageous to maximize each of the above relationships while still maintaining a good clearance for proper operation of the reel assembly 120. Thus, for example, the above-described relationship is selected to be as large as possible while still keeping the housing 110 as small and light as possible while still enabling the reel assembly 120 and the self-retracting assembly 130 to operate properly. The above-specified relationships may be followed for any size of tape measure device 100 in order to obtain an optimal balance between minimizing weight and size while maximizing strength and durability.

As best shown in fig. 8, one or both of first and second half shells 112 and 114 may include mating features that extend from and are received by corresponding portions of first and second half shells 112 and 114. The mating features may include a protruding member extending perpendicularly away from a respective one of the first and second mating surfaces 230 and 232 and a corresponding receiving slot shaped to receive the respective one of the protruding members. Some protruding members (e.g., housing alignment protruding member 260) may be formed to correspond to edges of the sidewalls 210 or 212 and/or edges defining the receiving opening 220. Other protruding members (e.g., boss alignment protruding member 270) may be formed to facilitate alignment of screw boss 240 when first and second housing halves 112 and 114 are joined together. As used herein, the term "protruding member" may thus be understood to refer to either or both of housing alignment protruding member 260 and boss alignment protruding member 270.

In this example, the first half shell 112 includes a shell alignment projecting member 260 and a boss alignment projecting member 270, and the second half shell 114 includes corresponding receiving slots 262 and 272, which may be shaped to receive a respective one of the projecting members. However, it should be understood that all or some of the protruding members may extend from the second half shell 114 into respective instances of the receiving slots 262 and 272 positioned at the first half shell 112.

In this example, some protruding members may be longer than others. In this regard, all of the projecting members may have substantially the same length (e.g., 0.110 inches) except for the projecting members in the critical area. Based on experience with the failure mode, and based on testing with the failure mode, the bottom portion of the housing 110 (i.e., the portion of the housing 110 along which the blade 140 extends before exiting the aperture 150) can be considered a critical area because it is most susceptible to failure during an impact event. Thus, at least some of the protruding members in the critical region may have a length that is about 50% (e.g., 45% to 55%) longer than the other protruding members. In this example, the housing alignment projecting member 260' located in the critical area is approximately 50% longer than the other projecting members. Thus, in this example, the housing alignment projecting member 260' in the critical area is about 0.165 inches long. The housing alignment projecting members 260' in the critical area may also or alternatively have a length selected to be about 8.8% of the width (W) of the housing 110. Thus, for example, the housing alignment projecting member 260' in the critical region may have a length of about 8.3% to about 9.3% of the width (W) of the housing 110.

In an exemplary embodiment, a tape measure device is provided. The tape measure device may include a housing having an aperture, a reel assembly enclosed within the housing, and a blade having a first end configured to extend from the housing through the aperture and a second end configured to be wound on the reel assembly. The housing may include a first half shell and a second half shell. The reel assembly may be configured to alternately allow the blade to be drawn from the reel assembly through the aperture or received in the aperture onto the reel assembly. The first and second half shells may be joined together via threaded fasteners inserted into respective portions of screw bosses formed in corresponding portions of the first and second half shells. Mating features may be provided on the first and second half shells to facilitate joining the first and second half shells. At least some of the mating features may be longer than others, or the diameter of the screw boss may be about 1.5 to 2.5 times the diameter of the threaded fastener.

In some embodiments, features of the apparatus described above may be added or modified, or additional features may be added. These additions, modifications, and additions may be optional and may be provided in any combination. Thus, while some exemplary modifications, additions and additions are listed below, it should be understood that any of the modifications, additions and additions may be implemented individually or in combination with one or more or even all of the other modifications, additions and additions listed. Thus, for example, in some cases, at least some mating features may be longer than others, and the diameter of the screw boss may be about 1.5 to 2.5 times the diameter of the threaded fastener. In some cases, at least some mating features may be about 45% to about 55% longer than other mating features. Alternatively or additionally, at least some of the mating features are about 8.3% to about 9.3% of a total width of the first and second half-shells. In an exemplary embodiment, at least some of the mating features may include a protruding member disposed at the first half shell to extend into a corresponding receiving slot disposed at the second half shell. In some cases, the protruding member may be a housing alignment protruding member disposed at a bottom portion of the housing along which the blade extends before extending through the aperture. In an exemplary embodiment, the mating feature may comprise a protruding member provided only on the first half-shell to extend into a corresponding receiving slot provided only on the second half-shell. In some cases, the diameter of the screw boss may be about 7.8% to about 8.8% of the defined diameter of the first and second half shells. In an exemplary embodiment, the screw boss occupies about 2% to about 3% of the cross-sectional area enclosed by the first and second half shells. In some cases, the screw boss has a diameter of about 7.8% to about 8.8% of the defined diameter of the first and second half shells, and the screw boss occupies about 2% to about 3% of the cross-sectional area enclosed by the first and second half shells.

Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Moreover, although the foregoing descriptions and the associated drawings describe exemplary embodiments in the context of certain exemplary combinations of elements and/or functions, it should be appreciated that different combinations of elements and/or functions may be provided by alternative embodiments without departing from the scope of the appended claims. In this regard, for example, different combinations of elements and/or functions than those explicitly described above are also contemplated as may be set forth in some of the appended claims. Where advantages, benefits, or solutions to problems are described herein, it should be understood that these advantages, benefits, and/or solutions may apply to some example embodiments, but not necessarily all example embodiments. Thus, any advantages, benefits or solutions described herein should not be considered critical, required, or essential to all embodiments or embodiments claimed herein. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation.